Apparatus for increasing volumetric efficiency



P. s. TICE 1,957,919

APPARATUS FOR INCREASING VOLUMETRIC EFFICIENCY May 8, 1934.

Filed Fb. 2a. 1930 Patented May 8, 1934 APPARATUS FOR. INCREASING votUME'rmo nmomnor Percival S. Tice, I Chic ago, 111., assignor to Stewart-Warner Corporation, Chicago, 111., a

corporation of Virginia Application February 26,

1930, Serial No. 431,378

6 Claims. (01. 123-122) The purpose of this invention is to provide an improved construction in a carbureter for an internal combustion engine, particularly on an automotive vehicle, for avoiding the decrease of volumetric eficiency due to pre-heating of the fuel mixture or any element thereof before its delivery to the engine. The invention consists in the elements and features of construction shown and described, and the method stated, as indim cated in the claims.

In the drawing:-

Figure 1 is a diagrammatic view in the nature of a side elevation of an engine having its carbureter equipped with this invention.

Figure 2 is a detail vertical longitudinal section through the air conduit which constitutes the feature of the invention at its extent through the radiator for showing its relation to the radiator and radiator shutters.

Figure 3 is a detail front elevation showing a part of the radiator with shutters at open position showing behind their openings the entrance mouth of the air conduit.

It is well understood that the volumetric efiiciency and power output of an internal combustion engine depending on the increase of volume of the energizing fuel due to ignition and combustion, is reduced to a substantial degree by heating and consequent expansion of the fuel mixture or any element thereof, before its delivery to the engine, and in the present invention I aim to avoid this loss of efficiency by avoiding certain pre-heating of the air component of the fuel mixture which is incident to the present commonly 5 prevailing methods of construction and arrangement of the, fuel mixture conduit with respect to the carbureter and the engine. In substantially all constructions and installations of an internal combustion engine on a motor vehicle with which I am familiar, the main air supply for the fuel mixture is taken from under the engine hood,

where, when the engine is running, the air is very substantially heated above atmospheric temperature. And in recent carbureter constructions, an

arrangement commonly referred to as downdraft carbureter,the air intake to the carbureter being at the upper side and above the level of the intake manifold, is of course at the upper part of the hood, where the air is hottest, the embarrassment and loss of efficiency due to preheating the air is very serious.

From actual observation and tests, I have ascertained that under the conditions of atmospheric temperature at F., the average difierence between this atmospheric temperature and the temperature at the upper part of the hood, at which the air intake to the down-draft carbureter is located, is about 90 F., the temperature under the hood being 150 F. And it may be readily computed that the avoidance of this increase of tem- 60 perature from 60 F. to 150 F..would yield a power increase of 5.5%. And under winter conditions with the atmosphere temperature at 30 F., I have found the temperature under the hood at the in-' take of the down-draft carbureter to be 90 F., from which it may be computed that the gain of eificiency by avoiding this increase and supplying the carbureter with atmospheric temperature, would amount to 6.5%. v

These increases are based solely on the difference in temperature of the air supply to the carbureter; and it is entirely possible by suitably designing and selecting the area and location of the air duct entrance to effect super-atmospheric pressure in the duct due to the impact pressure resulting from the forward motion of the vehicle in travel. If this pressure is utilized, further increase of the air pumping capacity of the engine would further increase the power output.

These gains of efliciency I have undertaken to so obtain by the construction shown in the drawing, in which the engine body indicated in totality by reference letter, A, is shown equipped with a down-draft carbureter indicated at E, having its main air intake at 20, with the air conduit, 21, 35 extending upwardly andforwardly from said intake under the hood, indicated at D, to the forward end of the engine, and through the radiator body, indicated at B, and provided at the upper part with an aperture through which the conduit, 21, comprising a sleeve, 22, extends, said conduit having its intake manifold indicated at 25 at the forward side of the radiator body and behind the shutter system indicated at C.

As a matter of detail, it is desirable to provide a perforated screen, as shown at 26, in the forward portion of the conduit, 21, for excluding dust and insects, and also at the connection with the carbureter intake and air cleaning screen, indicated at 23.

An advantage gained by terminating the con-- duit, 21, for positioning its intake mouth behind the shutters, consisting in thatwhen starting the engine cold, before the jacket water becomes warmed to a temperature at which the shutter will be opened in any desired way commonly provided for that purpose the warming up of the engine to this degree is maintained, or,-more correctly speaking,avoidance of delay which would be caused by the cold air coming into the carbureter through the cold pipe, 21, is effected, by taking advantage of the initial warming up of the radiator before the shutters open for warming the air which passes through the conduit, 21, to the carbureter.

I claim:

1. In combination with an internal combustion engine carbureter of a motor vehicle having a radiator for cooling the engine and provided with shutter means excluding and admitting atmospheric air for cooling the radiator, an air supply pipe extended from the carbureter intake forwardly to the front of the engine to a point behind the shutter, and open for intake of atmospheric air at a point forward of any substantially heated portion of the engine body; whereby the air for the explosive mixture delivered to the engine is furnished to the engine intake at approximately atmospherc temperature and with an increasing volume as the speed of the vehicle increases due to the impact pressure upon the forward end of the air supply pipe.

2. In combination with an internal combustion engine carbureter of a motor vehicle having a radiator for cooling the engine and provided with shutter means excluding and admitting atmospheric air for cooling the radiator, an air supply pipe extended from the carbureter intake forwardly to the front of the engine to a point behind the shutter, and open for atmospheric intake at a point forward of the heated body of the radiator, whereby the air for the explosive'mixture delivered to the engine is furnished to the engine substantially without increase of temperature by the heat of the engine body and with an increasing volume as the speed of the vehicle increases due' to the impact pressure upon the forward end of the air supply pipe.

3. In combination with an internal combustion engine of a motor vehicle having a radiator and provided with a shutter means excludng and admitting atmospheric air for cooling the radiator. an air supply pipe extended from the carbureter intake forwardly to the front of the engine to apoint behind the shutter and through the radiator body, and open at the forward end for atmosphere intake at the forward side of the radiator, whereby the air for the explosive mixture delivered to the engine is furnished to the engine with an increasing volume as the speed of the vehicle increases due to the impact pressure upon the forward end of the air supply pipe.

4. In combination with an internal combustion engine carbureter of a motor vehicle having a radiator for cooling the engine, and provided with shutter means excluding and admitting atmospheric air for cooling the radiator, an air supply pipe extending from the carbureter intake forward to the front of the engine and through the radiator body, open at the forward end forwardly of said radiator body and behind the shutter means; whereby the air for the explosive mixture delivered to the engine is derived directly from the atmosphere without passing through the radiator or over the engine body in a manner for deriving heat therefrom when the shutter is open, and said atmospheric air furnished to the carbureter when the shutters are closed and while the engine is beingwarmed to desirable temperature, is concurrently warmed to such desirable temperature.

5. In combination with an internal combustion engine of a motor vehicle having a radiator for cooling the engine and provided with shutter means excluding and admitting atmospheric air for cooling the radiator, a down-draft carbureter for delivering a fuel mixture to the engine, an air intake pipe for said carbureter leading from the upper end of said carbureter forwardly of the engine to a point behind the shutter and through the radiator for the engine, said air intake pipe being open at its forward end to receive an impact air pressure due to movement of the vehicle.

6. In combination with an internal combustion engine carbureter of a motor vehicle having a radiator for cooling the engine and provided with shutter means controlling the admission of air for cooling the radiator, an air supply pipe extending from the carbureter intake forwardly to a point between the radiator and the shutter where it is open for the admission of air.

PERC'IVAL S. TICE. 

